The crackdown comes after the high-profile case of medical student Hester Stewart, 21, who died in Brighton in April after taking GBL.

Her mother, Maryon Stewart, said the new rules did not go far enough because GBL had been classified only as a Class C illegal drug. “In America, it is schedule A, which is the equivalent of a Class A drug here,” she said.

The home secretary, Alan Arthur Johnson, said: “We are sending out a clear message to anyone who is thinking about experimenting with [the drugs], particularly over the festive period, that not only are they putting themselves in danger, they will also be breaking the law.”

Fifteen anabolic steroids are also to be controlled as class C drugs, alongside two growth promoters.